Bruce knew he had a sense of humor. He just knew that what he found funny wasn't anything that anyone else found funny. Essentially what that meant was that, to the population at large, Bruce Wayne was not a funny man.
He liked teasing Clark because the man was a good enough friend to at least know he was capable of making a joke, in his own dry, practically humorless way, but was also never sure when he was really kidding, and when he wasn't.
Which was something Bruce found just as funny as the joke itself.
Never truly surprised to see his friend whenever he found Clark in the Batcave, Bruce pulled the car onto the circular dias and got out, not looking Superman's direction as he headed down to the second level toward the locker room to shower and change into civilian clothes. He didn't look back to see that Clark would follow, he knew he would be. Just as he knew he'd wait outside the locker room and even turn his back to afford him privacy while he stripped out of the sweaty uniform and under the water, despite the walls separating them.
"I hear you've joined Fury's Foot Soldiers," he commented, deceptively mild.